The most common of the pediatric neurodegenerative diseases (1 in 12,500 births) are a set of primarily recessive disorders termed Neuronal Ceroid Lipofuscinoses (NCLs) due to the loss of central nervous system neurons and the accumulation of auto-fluorescent lipopigment. While most cells contain inclusions, neurons are primarily affected leading to symptoms that include loss of vision, motor dysfunction, intellectual decline, and seizures. Infantile onset NCL (INCL) is the earliest and most severe form of NCL. INCL is caused by mutations in the CLN1 gene which encodes palmitoyl-protein thioesterase 1 (PPT1), suggesting that there is an important role for the regulation of palmitoylation in normal neuronal function. While recent work is beginning to shed light on the protein's localization and function, there is still little understanding of the role PPT1 plays in different cellular compartments, including tissue specific substrates and signaling pathways that it may modulate. We have turned to the powerful genetic tools available in Drosophila to begin to address these questions. We have previously shown that targeted overexpression of DmPptl in the developing Drosophila visual system produces retinal degeneration. We plan to use this phenotype to perform genetic modifier screens to identify genes that modify the degeneration. Successful completion of these aims will produce a collection of genes that will provide insight into the cellular pathway(s) connected to Ppt1 function. The recent determination of a protein interaction map for the Drosophila proteome has generated a wealth of protein-protein interaction data that must now be validated experimentally. The yeast two-hybrid approach identified a "high confidence" interaction between DmPpt1 and the ankyrin domain-containing protein CG5846. We aim to further characterize the DmPpt1-CG5846 interaction both biochemically and functionally. Successful completion of this proposal will begin to shed significant light on the role of this gene in the pathogenesis of Infantile Neuronal Ceroid Lipofuscinoses. This will have consequences not only for identification of possible therapeutic strategies, but it will also begin to elucidate the possible functions of Ppt1 in neural apoptosis, signal modulation at the synapse, and membrane and protein trafficking. [unreadable] [unreadable]